This is a national phase application based on WO 00/53857 (PCT/DE99/00678), filed on Sep. 14, 2000.
The invention describes an arrangement for the automatic cleaning and disinfection of drain traps in drain channels. The cleaning and disinfection take place automatically during normal usage and without interrupting the operation of the drain trap. They take place by means of a combination, novel for drain traps, of electromechanical oscillation, of low-frequency oscillations up to ultrasonic irradiation, heating of the inner area of the drain trap and of the confining or sealing liquid and by preventing growth on the inner wall by means of a growth-inhibiting and antimicrobially efficacious coating.
The danger of a microbic recontamination of sanitary apparatuses and devices and therewith also of the air in the room by microorganisms from drain channels has long been known and feared, particularly in the clinical area; however, it presents a general hygienic problem in areas of common usage of sanitary devices.
Drain channels with zones of low or sharply fluctuating flowthrough rate such as, e.g., drain traps integrated in them in which traps waste water functions at the same time as drain-trap medium are, as is known, places where microorganisms reside and multiply. At times, optimal preconditions for the survival and multiplication of germs dangerous to health prevail in drain traps. The microbial recontamination of sanitary devices (e.g., washbasins) and of room air takes place in the following manner:
When liquid impacts and becomes turbulent, aerosols are produced consisting of minute droplets of liquid that also contain all microorganisms contained in the confining liquid. Such aerosols are produced, e.g., when water cocks of washbasins are opened in the drain area. These aerosols then contain representatives of all of the microorganisms present in the liquid in the siphon and present in the slime layers adhering to the inner walls.
The aerosols formed are displaced by subsequent water flowing out of the hollow area in the direction of the pipeline or channel entrance and therefore pass into the air of the room from which the waste water was placed into the pipeline. In this manner, e.g., these bacteria can be transferred onto the hands of a person washing up in the washbasin.
This, for its part, results in the sufficiently known and frequently described hygienic problems, especially in infection stations of hospitals, particularly as regards the feared bacterium Pseudomonas aeruginosa. 
Moreover, microbes form the known, slimy coating together with dirt particles on the inner wall of the pipeline or of the siphon. This coating grows, largely invisible to the eye at times, out of the opening of the drain into the washbasin.
The prevention of the adhering of microorganisms and dirt particles on the inner walls of drain traps and the simultaneous killing of microorganisms in drain traps is an important problem that has, however, not been technically solved up to the present day, especially as regards the dangerous occurrence of antibiotic-resistant microorganisms such as the bacterium Pseudomonas aeruginosa, that is extremely feared in the clinic.
Developments for drain channels and siphons have been described that make use of the germicidal properties of high temperature (DE 4206901, U.S. Pat. No. 4,192,988), ultraviolet radiation in liquids (DE 4206901, DE 4025078 A1, DE 29509210 U1). Developments for cleaning and disinfecting siphons and pipelines with ultrasound are also known (DE 27 47 992 A1, U.S. Pat. No. 3,175,567).
The combination of ultraviolet light and ultrasound (DE 295 09 210 U1) is not described for the cleaning and disinfecting of pipelines and siphons but is described for the cleaning and disinfecting of objects in liquids. The combination of ultraviolet light and high temperature (DE 42 06 901 A1) is described for treating liquid in a siphon.
The combination of the effect of electromechanical oscillations, in particular ultrasound with elevated temperature has not yet been described for drain traps.
All known inventions take into account partial aspects of the total events in a pipeline or a siphon and offer solutions for them.
These partial solutions have such disadvantages in practice that up to the present none of the solutions has found acceptance in clinics even though many application tests have been carried out with these systems, some even over a rather long time period.
The sole use of high temperatures for long time periods results, as a consequence of the drying of dirty water occasioned by evaporation, in augmented coatings of the inner walls of pipelines and siphons.
The drain traps clog up and lose their function. In the approach area the dry wall coating is altematingly re-moistened by subsequent water flowing in and constitutes a very good path for recontamination. In addition, high evaporation losses and incrustations can suppress the operation of the drain trap or clog the pipeline. However, the killing of pathogenic germs is not assured until at temperatures that significantly advance the evaporation of the liquid and therewith the wall coating.
The effectiveness of the use of ultraviolet light in liquids is very much a function of the degree of contamination of the drain [waste] water and of the penetration (transmission) conditioned by it. In addition, a few, in particular pathogenic germs such as, e.g., legionellas can not be reached or are difficult to kill with UV irradiation alone.
The -effect of high temperature and ultraviolet light can result in an insufficient killing of germs, especially in the case of highly contaminated and possibly infectious liquids like those usually found in clinical practice on account of a low penetration capability and can also not prevent the growth on walls and therewith recontamination via this path. The effectiveness of ultrasound on the killing of germs is temperature-dependent. Since the temperature of the liquid in pipelines and drain traps is a function of many factors and therefore fluctuates, the killing effect by ultrasound alone also fluctuates and can therefore not be completely defined even in the case of maximum acoustic irradiation.
At room temperature, for example, the killing effect in the case of logically installable ultrasound outputs (e.g., 300-1000 watts/liter) is possible only given relatively long irradiation times (one hour and longer) whereas at temperatures of 50xc2x0 C. already a few minutes are sufficient. At this temperature there is still no killing of microorganisms by the heat alone.
Moreover, it is necessary in practice to carry out the irradiation at intervals and to keep the irradiation time as short as possible thereby. On the other hand, economy and the noise level require the installation of the lowest possible ultrasound intensities. The irradiation at intervals of the inner space of the drain trap results, especially at rather high temperatures, in the loosening of existing wall coatings and prevents a new coating at the same time.
The present invention entails a self-disinfecting drain trap that solves the problem of the multiplication and exiting of microorganisms from drain pipelines with reliability and reproducibility not available with the current state of the art by the maximum and consistently reproducible killing of germs, preventing the growth on the inner walls of drain traps and the exiting of aerosols contaminated with living germs from pipelines and that does not exhibit the previously cited disadvantages of known developments.
Thus, the following effects are achieved in an apparatus by the self-disinfecting drain trap of the invention:
1. Microorganisms of all types are killed in a reproducible manner always under the same conditions at a sufficiently high temperature, sufficient ultrasound intensity and a treatment time assuring a complete killing of germs by the invention during its proper usage.
2. A settling of microorganisms and dirt particles and the multiplication of microorganisms is made significantly more difficult by a liquid-repelling and/or antimicrobially active coating of the inner wall of the drain trap.
3. The air in the inner space of the drain trap can be additionally disinfected by ultraviolet light.
4. The invention prevents the formation of the known coating of dirt and microorganisms by means of a special anti-adhering coating of the inner wall or by the use of suitable material for the reaction area.
5. The invention prevents microorganisms from settling on the siphon wall by means of low-frequency electromechanical oscillations and dissolves coatings already present during normal usage.